un example:
#burg
----------------
Obj=building
copyright=mobo
name=p32c_cur_10_01
type=cur # important!
needs_ground=1
level=10
Build_time=0
climates=arctic,rocky,tundra,temperate
Dims=2,2,1
BackImage[0][0][0][0][0][0]=burg.0.0
BackImage[0][0][1][0][0][0]=burg.0.1
BackImage[0][1][0][0][0][0]=burg.1.0
BackImage[0][1][1][0][0][0]=burg.1.1
BackImage[0][0][0][1][0][0]=burg.2.0
BackImage[0][0][1][1][0][0]=burg.2.1
BackImage[0][1][0][1][0][0]=burg.3.0
BackImage[0][0][0][0][0][1]=burg.0.2
BackImage[0][0][1][0][0][1]=burg.0.3
BackImage[0][1][0][0][0][1]=burg.1.2
BackImage[0][1][1][0][0][1]=burg.1.3
BackImage[0][0][0][1][0][1]=burg.2.2
BackImage[0][0][1][1][0][1]=burg.2.3
BackImage[0][1][0][1][0][1]=burg.3.2
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